PurposeThe purpose of this article is to present a subsection circulatory management (SCM) model of Library 2.0. The design idea of Library 2.0 system architecture is to be illustrated and a five‐tier model of service‐oriented architecture (SOA) is to be put forward and analyzed.Design/methodology/approachThe SOA model conforms to the desires of Library 2.0. Libraries require integration of literature resources, knowledge services and operations management and together all these integrations must be based on the user service. The realization of the concept and technology of Library 2.0 is similar with the SOA model.FindingsCurrent library management systems (LMS) remain at the era of Library 1.0, which focused on literature management. The new design principles are aiming to manage library resources much better. Library 2.0 must break through the current framework, and adopt a multilayer structure, user‐centered and service‐oriented system architecture to integrate the resources, the services and managements. Amongst other things, Library 2.0 should utilize the multilayer architecture based on the module mode, improve the flexibility and adaptability of modern management systems, both in system configuration and operational management.Originality/valueThe SOA model is applied in Library 2.0 for the first time and is divided into five tiers – hardware tier, system tier, data tier, operation management tier and knowledge service tier. According to the architecture, three application systems – LMS based on librarians, knowledge service system based on patrons, and knowledge search engine, are designed.
PurposeIt is important for digital library to attract users to be reliant on the library. Besides providing research resources, the library still has many ways to achieve this goal. This article aims to experiment on the library merit system which provides different ways to enhance users' viscosity on using library.Design/methodology/approachFor the experiment, a merit system was developed and implemented; users' feedback was collected by a questionnaire survey for analysis.FindingsThe results showed that the degree of users' viscosity on the digital library was increased and several areas for a successful digital library portal should be paid more attention to.Originality/valueThe merit system can successfully increase users' viscosity with digital library.
Enoyl-CoA hydratase (ECH), which is also known as crotonase, is the second requisite enzyme in the β-oxidation pathway of fatty acid that catalyzes the syn hydration of α,β-unsaturated thiolester substrates. In this work, ECH-catalyzed hydration mechanisms of DAC-CoA and Crotonyl-CoA were investigated using density functional theory (DFT) methods. Geometrical structures were optimized using Gaussian 03 program at the B3LYP/6-31G(d,p) level of theory. Frequency calculations were performed with the 6-31G(d,p) basis set to obtain zero-point vibrational energies (ZPEs) and to confirm the nature of all the stationary points that have no imaginary frequency for the local minima and have only one imaginary frequency for the saddle points. The single-point calculations on the optimized geometries were further performed with 6-311+ +G(2d,2p) basis set to obtain more accurate energies. The polarizable-continuum model (PCM) with the dielectric constant of 4 was used to calculate the single point energies at 6-311++G(2d, p) level on all the optimized geometries to consider the effects of enzymatic environment that was not included in the computational model. Given that B3LYP functional lacks the proper description of the long-range dispersion interactions, an empirical dispersion correction was further calculated using the DFT-D3 method to correct the B3LYP energies. The final energies reported in this work are the single-point energies corrected for ZPEs, solvation and dispersion effects. The calculated results suggested that hydration proceeds through a stepwise mechanism, involving an enolate intermediate. Glu164 functions as the sole base/acid for catalysis. Although Glu144 is not directly involved in hydration, it induces the catalytic water molecule to locate an ideal orientation to attack the double bond of substrate by the hydrogen-bonding interaction. Crotonyl-CoA shows higher hydration activity than DAC-CoA. The backbone NH groups of Ala98 and Gly141 form an oxyanion hole with substrate carbonyl oxygen, which play key roles in binding substrate and stabilizing the generated transition states and intermediates. In addition, the hydrogen-bonding networks surrounding Glu144 and Glu164 are of great importance for active site arrangement.
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